1. Field
One or more embodiments described herein relate to a light-emitting display device, and a method of manufacturing a light-emitting display device.
2. Description of the Related Art
An organic light-emitting display is self-luminous and has a wide viewing angle, high contrast ratio, and fast response time. Each pixel of this display has an organic light-emitting layer between an anode electrode and cathode electrode.
When positive and negative voltages are applied to these electrodes, holes move from the anode electrode to the organic light-emitting layer via a hole injection layer and a hole transport layer, and electrons move from the cathode electrode to the organic light-emitting layer via an electron injection layer and an electron transport layer. The electrons and holes recombine in the organic light-emitting layer to generate excitons. As the excitons change from an excited state to a ground state, the organic light-emitting layer emits light to form an image.
The organic light-emitting display may also include a pixel defining layer having an opening that exposes the anode electrode of each pixel. The hole injection layer, the hole transport layer, the organic light-emitting layer, the electron transport layer, the electron injection layer, and the cathode electrode may be formed on the anode electrode, which is exposed through the opening of the pixel defining layer. The hole transport layer and the organic light-emitting layer may be formed using, for example, an inkjet print method or a nozzle print method.
A lyophilic surface processing layer may be formed on the anode electrode, for example, to improve wettability of a hole transport layer solution. However, when the hole transport layer solution is ejected onto the surface processing layer, the solution may errantly spread toward an adjacent pixel due to its ejection pressure and speed.
As a result, the hole transport layer may be formed up to part of the adjacent pixel. The organic light-emitting layer may also be formed on the hole transport layer up to part of the adjacent pixel. Therefore, organic light-emitting layers that emit light of different colors may overlap each other in adjacent pixels. Consequently, an unwanted mixed color may be displayed, to thereby degrade display quality.